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It took a year to ship WebAssembly in Anubis

2026-09-06 | original

read original get Programming WebAssembly with Rust (Kevin Hoffman) → more articles

Why This Matters

The article body didn't load — instead it shows Anubis's own interstitial, the proof-of-work gate that sites deploy to blunt aggressive AI scraping. That's a fitting illustration of the story: defensive tooling against scrapers is now common enough that ordinary readers routinely hit JavaScript challenge pages, with real costs to accessibility and user experience.

Key Takeaways

Anubis uses a Hashcash-style proof-of-work challenge to make mass scraping expensive while barely taxing individual visitors.
Its maintainers frame it as a stopgap; the longer-term aim is fingerprinting headless browsers so real users skip the challenge.
The approach breaks for users with JavaScript-restricting privacy plugins, highlighting the tradeoff between anti-scraping defenses and open web access.

Worth a Look

Programming WebAssembly with Rust (Kevin Hoffman) — If a story about shipping WebAssembly in Anubis makes you curious how Wasm actually works, this book walks through building and running WebAssembly modules with Rust from the ground up. It's a practical way to understand the toolchain behind browser-side proof-of-work and other compute-heavy web workloads.

See Programming WebAssembly with Rust (Kevin Hoffman) on Amazon → Affiliate link — we may earn a commission on purchases, at no extra cost to you. Product picked by AI based on this article; it is not a tested recommendation.

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Anubis could not load its JavaScript. The server may be overloaded. Please reload the page to try again.

You are seeing this because the administrator of this website has set up Anubis to protect the server against the scourge of AI companies aggressively scraping websites. This can and does cause downtime for the websites, which makes their resources inaccessible for everyone.

Anubis is a compromise. Anubis uses a Proof-of-Work scheme in the vein of Hashcash, a proposed proof-of-work scheme for reducing email spam. The idea is that at individual scales the additional load is ignorable, but at mass scraper levels it adds up and makes scraping much more expensive.

Ultimately, this is a placeholder solution so that more time can be spent on fingerprinting and identifying headless browsers (EG: via how they do font rendering) so that the challenge proof of work page doesn't need to be presented to users that are much more likely to be legitimate.

Please note that Anubis requires the use of modern JavaScript features that plugins like JShelter will disable. Please disable JShelter or other such plugins for this domain.

Explore topics: anubis webassembly proof-of-work hashcash web scraping